audit: type=1800 audit(1584817433.804:133): pid=20426 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=collect_data cause=failed(directio) comm="syz-executor.3" name="file0" dev="sda1" ino=16844 res=0 audit: type=1804 audit(1584817433.804:134): pid=20426 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.3" name="/root/syzkaller-testdir631788731/syzkaller.K8vHf5/543/file0" dev="sda1" ino=16844 res=1 ================================================================== BUG: KASAN: use-after-free in memcpy include/linux/string.h:348 [inline] BUG: KASAN: use-after-free in soft_cursor+0x448/0xa20 drivers/video/fbdev/core/softcursor.c:70 Read of size 9 at addr ffff8880a7840e00 by task syz-executor.4/20423 CPU: 1 PID: 20423 Comm: syz-executor.4 Not tainted 4.19.112-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 print_address_description.cold+0x7c/0x212 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold+0x88/0x2b9 mm/kasan/report.c:396 memcpy+0x20/0x50 mm/kasan/kasan.c:302 memcpy include/linux/string.h:348 [inline] soft_cursor+0x448/0xa20 drivers/video/fbdev/core/softcursor.c:70 bit_cursor+0x1230/0x1900 drivers/video/fbdev/core/bitblit.c:386 fbcon_cursor+0x572/0x760 drivers/video/fbdev/core/fbcon.c:1369 hide_cursor+0x99/0x2f0 drivers/tty/vt/vt.c:895 redraw_screen+0x2ed/0x870 drivers/tty/vt/vt.c:999 vc_do_resize+0x109e/0x13a0 drivers/tty/vt/vt.c:1298 vt_ioctl+0x1dff/0x2310 drivers/tty/vt/vt_ioctl.c:891 tty_ioctl+0x7a1/0x1420 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c849 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f5f08bcec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f5f08bcf6d4 RCX: 000000000045c849 RDX: 0000000020000040 RSI: 000000000000560a RDI: 0000000000000003 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000066a R14: 00000000004c93e6 R15: 000000000076bf0c Allocated by task 19944: set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:531 __do_kmalloc mm/slab.c:3727 [inline] __kmalloc_track_caller+0x153/0x770 mm/slab.c:3742 kmemdup+0x23/0x50 mm/util.c:118 kmemdup include/linux/string.h:421 [inline] cache_create_net+0x2e/0x230 net/sunrpc/cache.c:1687 nfsd_export_init+0x257/0x470 fs/nfsd/export.c:1243 nfsd_init_net+0x163/0x460 fs/nfsd/nfsctl.c:1236 ops_init+0xaf/0x410 net/core/net_namespace.c:129 setup_net+0x2c2/0x6f0 net/core/net_namespace.c:315 copy_net_ns+0x1d9/0x331 net/core/net_namespace.c:438 create_new_namespaces+0x3fb/0x7c0 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:206 ksys_unshare+0x439/0x8d0 kernel/fork.c:2530 __do_sys_unshare kernel/fork.c:2598 [inline] __se_sys_unshare kernel/fork.c:2596 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:2596 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8209: set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0xf7/0x140 mm/kasan/kasan.c:521 __cache_free mm/slab.c:3503 [inline] kfree+0xce/0x220 mm/slab.c:3822 nfsd_export_shutdown+0x20b/0x371 fs/nfsd/export.c:1286 ops_exit_list.isra.0+0x9d/0x140 net/core/net_namespace.c:153 cleanup_net+0x3bf/0x850 net/core/net_namespace.c:553 process_one_work+0x91f/0x1640 kernel/workqueue.c:2155 worker_thread+0x96/0xe20 kernel/workqueue.c:2298 kthread+0x34a/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 The buggy address belongs to the object at ffff8880a7840d00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 256 bytes inside of 512-byte region [ffff8880a7840d00, ffff8880a7840f00) The buggy address belongs to the page: page:ffffea00029e1000 count:1 mapcount:0 mapping:ffff88812c3dc940 index:0x0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea000225b548 ffffea00024f1188 ffff88812c3dc940 raw: 0000000000000000 ffff8880a7840080 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a7840d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a7840d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a7840e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a7840e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a7840f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================